A trailer is a non-motorized or unpowered vehicle designed to be hauled or pulled over a road or other surface by a motor-powered vehicle such as an automobile or a truck. Trailers are used to transport an almost countless number of different things. For that reason, there are a large number of different types and sizes of trailers that can be attached to towing vehicles that can include automobiles and all sizes and kinds of trucks.
Trailering, i.e., transporting something by means of a trailer, requires a vehicle that is mechanically capable of pulling a trailer safely. It also requires skill. Perhaps more importantly, safely hauling something with a trailer requires knowledge of the trailer, its contents and its capabilities and knowledge of its operating characteristics.